A218213 Number of n-digit primes representable as sums of consecutive squares.

1, 4, 13, 30, 69, 187, 519, 1401, 3889, 10861, 31640, 90735

Offset

1,2

Comments

There are no common representations of two, three or six squares for n < 13, so

a(n) = A218207(n) + A218209(n) + A218211(n); n < 13.

Links

Table of n, a(n) for n=1..12.

Formula

a(n) = A218214(n) - A218213(n-1).

Mathematica

nn = 8; nMax = 10^nn; t = Table[0, {nn}]; Do[k = n; s = 0; While[s = s + k^2; s <= nMax, If[PrimeQ[s], t[[Ceiling[Log[10, s]]]]++];  k++], {n, Sqrt[nMax]}]; t (* T. D. Noe, Oct 23 2012 *)

Crossrefs

Cf. A027861, A027862, A027863, A027864, A027866, A027867, A218207, A218209, A218211.

Sequence in context: A206806 A022913 A232228 * A075880 A042487 A154753

Adjacent sequences: A218210 A218211 A218212 * A218214 A218215 A218216

Keyword

nonn,base

Author

Martin Renner, Oct 23 2012

Status

approved